"we know that close scrutiny is part of the process and we've been talking to the US Department of Justice over the past few weeks. Today we received what is called a 'second request', which means that the DOJ is asking for more information so that they can continue to review the deal," says senior VP Dennis Woodside in a blog post.

"While this means we won't be closing right away, we're confident that the DOJ will conclude that the rapidly growing mobile ecosystem will remain highly competitive after this deal closes."

Woodside describes the extra scrutiny as 'routine' - although, in fact, very few takeover deals are subjected to a second request for information. Routine for Google, maybe.

Google had initially hoped that the acquisition would go through by the end of the year. But when the company's received similar second requests for information before - for example with the takeovers of DoubleClick and AdMob - it's meant the process has been dragged out for months.

And with patent battles looming, it's time that Google can ill-afford to lose.